Arjun Dey is a core member of the Dark Energy Spectroscropic Instrument (DESI) survey project, the largest cosmic cartography project ever undertaken. DESI will provide the most precise measurements to date of the expansion history of the universe and the role of dark energy. In this program, Dr. Dey discusses the enigma of dark energy and the accelerating expansion of the universe, the scope of the DESI project, and the broad impact it will have on astrophysics and cosmology.